c05rb_a1w_f (sys_deriv_easy_a1w) : NAG AD Library Routine Document, Mark 27

NAG AD Library
c05rb_a1w_f (sys_deriv_easy_a1w)

Note: _a1w_ denotes that first order adjoints are computed in working precision; this has the corresponding argument type nagad_a1w_w_rtype. Further implementations, for example for higher order differentiation or using the tangent linear approach, may become available at later marks of the NAG AD Library. The method of codifying AD implementations in the routine name and corresponding argument types is described in the NAG AD Library Introduction.

2 Specification

Fortran Interface

Subroutine c05rb_a1w_f (

ad_handle, fcn, n, x, fvec, fjac, xtol, iuser, ruser, ifail)

Integer, Intent (In)	::	n
Integer, Intent (Inout)	::	iuser(*), ifail
Type (nagad_a1w_w_rtype), Intent (In)	::	xtol
Type (nagad_a1w_w_rtype), Intent (Inout)	::	x(n), ruser(*)
Type (nagad_a1w_w_rtype), Intent (Out)	::	fvec(n), fjac(n,n)
Type (c_ptr), Intent (In)	::	ad_handle
External	::	fcn

C++ Header Interface

#include <nagad.h>

void c05rb_a1w_f_ (

void *&ad_handle,
void (NAG_CALL fcn)(void *&ad_handle, const Integer &n, nagad_a1w_w_rtype x[], nagad_a1w_w_rtype fvec[], nagad_a1w_w_rtype fjac[], Integer iuser[], nagad_a1w_w_rtype ruser[], Integer &iflag),
const Integer &n, nagad_a1w_w_rtype x[], nagad_a1w_w_rtype fvec[], nagad_a1w_w_rtype fjac[], const nagad_a1w_w_rtype &xtol, Integer iuser[], nagad_a1w_w_rtype ruser[], Integer &ifail)

The routine may be called by the names c05rb_a1w_f or nagf_roots_sys_deriv_easy_a1w.

3 Description

c05rb_a1w_f is the adjoint version of the primal routine c05rbf.

c05rbf is an easy-to-use routine that finds a solution of a system of nonlinear equations by a modification of the Powell hybrid method. You must provide the Jacobian. For further information see Section 3 in the documentation for c05rbf.

5 Arguments

In addition to the arguments present in the interface of the primal routine, c05rb_a1w_f includes some arguments specific to AD.

A brief summary of the AD specific arguments is given below. For the remainder, links are provided to the corresponding argument from the primal routine. A tooltip popup for all arguments can be found by hovering over the argument name in Section 2 and in this section.

1: ad_handle – Type (c_ptr) Input

On entry: a handle to the AD configuration data object, as created by x10aa_a1w_f.

2: fcn – Subroutine External Procedure

The specification of fcn is:

Fortran Interface

Subroutine fcn (

ad_handle, n, x, fvec, fjac, iuser, ruser, iflag)

Integer, Intent (In)	::	n
Integer, Intent (Inout)	::	iuser(*), iflag
Type (nagad_a1w_w_rtype), Intent (In)	::	x(n)
Type (nagad_a1w_w_rtype), Intent (Inout)	::	fvec(n), fjac(n,n), ruser(*)
Type (c_ptr), Intent (In)	::	ad_handle

C++ Interface

#include <nagad.h>

void fcn (

void *&ad_handle, const Integer &n, nagad_a1w_w_rtype x[], nagad_a1w_w_rtype fvec[], nagad_a1w_w_rtype fjac[], Integer iuser[], nagad_a1w_w_rtype ruser[], Integer &iflag)

1: ad_handle – Type (c_ptr) Input: On entry: a handle to the AD configuration data object.
2: n – Integer Input
3: x – Type (nagad_a1w_w_rtype) array Input
4: fvec – Type (nagad_a1w_w_rtype) array Input/Output
5: fjac – Type (nagad_a1w_w_rtype) array Input/Output
6: iuser – Integer array User Workspace
7: ruser – Type (nagad_a1w_w_rtype) array User Workspace
8: iflag – Integer Input/Output

3: n – Integer Input

4: x(n) – Type (nagad_a1w_w_rtype) array Input/Output

5: fvec(n) – Type (nagad_a1w_w_rtype) array Output

6: fjac(n, n) – Type (nagad_a1w_w_rtype) array Output

7: xtol – Type (nagad_a1w_w_rtype) Input

8: iuser(

*

) – Integer array User Workspace

9: ruser(

*

) – Type (nagad_a1w_w_rtype) array User Workspace

10: ifail – Integer Input/Output

6 Error Indicators and Warnings

c05rb_a1w_f preserves all error codes from c05rbf and in addition can return:

$ifail = - 89$: An unexpected AD error has been triggered by this routine. Please contact NAG.
See Section 4.5.2 in the NAG AD Library Introduction for further information.

$ifail = - 899$: Dynamic memory allocation failed for AD.
See Section 4.5.1 in the NAG AD Library Introduction for further information.

Language	Source File	Data	Results
Fortran	c05rb_a1w_fe.f90	None	c05rb_a1w_fe.r
C++	c05rb_a1w_hcppe.cpp	None	c05rb_a1w_hcppe.r

NAG AD Library
c05rb_a1w_f (sys_deriv_easy_a1w)

▸▿ Contents

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

6 Error Indicators and Warnings

7 Accuracy

8 Parallelism and Performance

9 Further Comments

10 Example

NAG AD Libraryc05rb_a1w_f (sys_deriv_easy_a1w)

▸▿ Contents

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

6 Error Indicators and Warnings

7 Accuracy

8 Parallelism and Performance

9 Further Comments

10 Example

NAG AD Library
c05rb_a1w_f (sys_deriv_easy_a1w)